Seperating Slash and Markdown Commands (and keyboard Shortcuts) from the responsibility of the homepage component.

[diostoup1522]

Sub-issue related to #239.

The Task

The homepage component should not be responsible
for handling the functionality of the Markdown and Slash commands
and the functionality of the keyboard shortcuts.
Instead the logic has to be transfered to seperate components/modules
that will handle the underlying logic behind this functionality.
The goal of this change is moving away logic and reducing the responsibilities
and cognitive complexity of the homepage component.